Updating guidelines unofficial source (#6428)

* adding Malt Icon

* reverting a commit of the Malt icon directly to develop

* proposal for amendment to address Javascript and other icons without official sources

* proposal for amendment to address Javascript and other icons without official sources

* moved the new clause to the inside of the popular brand clause

* added a clause in the official icons guidelines

* Update CONTRIBUTING.md

Co-authored-by: Álvaro Mondéjar <mondejar1994@gmail.com>

* Update CONTRIBUTING.md

Co-authored-by: Eric Cornelissen <ericornelissen@gmail.com>

* Update CONTRIBUTING.md

Co-authored-by: Eric Cornelissen <ericornelissen@gmail.com>

* Update CONTRIBUTING.md

Co-authored-by: Sachin Raja <sachinraja2349@gmail.com>

* Update CONTRIBUTING.md

reduced the logo description to "widely accepted" rather than "well known or widely accepted de facto standard"

* removed bullet point at the insistence of Eric Cornelissen and Sachin Raja

* Update CONTRIBUTING.md

Co-authored-by: Álvaro Mondéjar <mondejar1994@gmail.com>

* changed source for Conda-Forge

* Update simple-icons.json

* Update simple-icons.json

* Update CONTRIBUTING.md

Co-authored-by: Sachin Raja <sachinraja2349@gmail.com>

Co-authored-by: jsoria <jsoria@tripadvisor.com>
Co-authored-by: Álvaro Mondéjar <mondejar1994@gmail.com>
Co-authored-by: Eric Cornelissen <ericornelissen@gmail.com>
Co-authored-by: Sachin Raja <sachinraja2349@gmail.com>

CONTRIBUTING.md

@@ -86,6 +86,9 @@ Official high quality brand logos and brand colors can usually be found in the f
 1. Wikimedia (which should provide a source)
 1. GitHub repositories
 
+It may be the case that no official source exists, but an unofficial icon has gained widespread acceptance and popularity. In such cases the unofficial icon can be included, but the details will be judged on a case-by-case basis. The JavaScript icon is an example of this.
+Notice that an unofficial source will never supersede an official one, even if it is more popular. An unofficial icon will only be accepted if no official option exists.
+
 #### Icon Guidelines
 
 Working with an SVG version of the logo is best. In the absence of an SVG version, other vector filetypes may work as well (e.g. EPS, AI, PDF). In the absence of vector logos, a vector can be created from a high quality rasterized image, however this is much more labor intensive.